Gupta et al U.S. Pat. No. 4,419,416 is concerned with an MCrAlY type overlay coating wherein M is nickel, cobalt, or mixtures thereof. In addition, the coating contains silicon and hafnium. The substrate may contain nickel, cobalt, tungsten, titanium, tantalum, aluminum and chromium.
U.S. Pat. No. 4,758,480 to Hecht et al is directed to protective coatings whose compositions are based on the compositions of the substrate. The coating comprises aluminum, chromium, hafnium, tantalum, yttrium and nickel while the substrate comprises nickel, aluminum, titanium, chromium and cobalt.
U.S. Pat. No. 4,801,513 to Duhl et al discloses a protective coating with an MCrAlY composition. The coating is applied to substrates including nickel, cobalt, aluminum, titanium, tantalum, tungsten and chromium.
U.S. Pat. No. 4,933,239 to Olson et al describes a protective NiCoCrAlY coating system which can be applied to a nickel base alloy. A diffusion zone may be included, and this zone is located between the substrate and an outer zone which contains the protective coating.